Process of coating metals with metal phosphides



Patented May 22, 1923.

1,456,252 PATENT OFFICE.

SAMUEL PEACOCK, 0F WHEELING, WEST VIRGINTA, ASSIGNOR TO.WHEELING STEEL8c IRON COMPANY, OF WHEELING, WEST VIRGINIA, A CORPORATION OF WEST VIE--GINIA.

No Drawing. 7 Application filed June 7,

To all "'z/lzom it may COW/067%.

Be. it known that I, SAMUEL PEACOCK, a citizen of the United'States,residing at lVheeling. in the'county of Ohio and State of West Virginia.have invented certain new and useful Improvements in Processes ofCoating Metals with Metal Phosphides; and I do hereby declare thefollowing to be a full, clear, and exact description of the inrention,such as will enable others skilled in the art to which. it appertains tomake and use the same.

This invention relates to a process of coat-. ing metal shapes ingeneral with protective films, consisting of phosphides andoxyphosphides of the metal to be coated, and has for its object toimprove the procedures and to lessen the cost of the processesheretofore proposed.

lVith these and other objects in view, the invention consists in thenovel steps and combinations of steps constituting the process, all aswill be more fully hereinafter disclosed and particularly pointed out inthe claims.

In carryin out this invention, I finely divide phosphate rock so that itwill pass say a hundred mesh screen, and I add finely divided carbonthereto, such as charcoal, or other carbon, which is substantially freefrom sulphur. To the mixture thus produced, I next add a suflicientquantity of a heavy oil to make apaint of a consistency that is easilyapplied to the metal to be coated. Instead of phosphate rock, I mayemploy any metal phosphate, such, for example, as sodium phosphate inmaking up the paint mixture, and the said paint mixture may beconveniently applied to the metal forms to be coated by any suitablemeans, such as a brush or by a dipping process.

If iron or steel forms are to be coated, it is not necessary to removethe ferro-ferric oxide coating that is usually present on these forms,because the reaction which takes place destroys this said black oxidecoating, as will presently appear.

After the said metal forms, for example, those of iron or steel, arethus painted or otherwise coated with the above mixture, their surfacesare heated by any suitable means in a non-oxidizing atmosphere to atemperature of about 1600 F., whereupon the tri-calcium phosphate 15decomposed PROCESS OF COATING METALS WITH METAL PHOSPHIDES.

1922-. Serial No. access.

with the formation of metal phosphides, and oxyphosphides on the surfaceof the metal belng coated. The carbon present reduces the ferro-ferricoxide coating on the iron and steel forms being treated, and thus leavesa clean iron orsteel surface with which the phosphides andoxyphosphides. immediately react to form on the surfaces of said iron orsteel objects protecting coatings of iron phosphides, and ironoxyphosphides. These coatings take a high polish,

.they are black in appearance, are pleasant up in stacks in suitableannealing boxes,

when the process of annealing also effects the formation of the ironphosphide coatings, thus rendering the entire process very much lesscostly than the prior procedures. When copper objects are coated in themanner above disclosed, they are likewise provided with protectivecoatings of copper phosphides, and copper oxyphosphides, and when thuscoated are found to be protected against corrosion in general exceptpossibly when brought into contact with strong'mineral acids.

It is obvious that those skilled in the art may vary the details of theprocedure Without departing from the spirit of the invention, andtherefore I do not wish to be limited to the above disclosure except asmay be required by the claims.

What is claimed is:

1. The process of coating metal shapes with protecting films whichconsists i making a mixture containing a phosphav e compound and carbonmixed with a viscous vehicle to form a paint; applying said paint to themetal surfaces to be protected; and

heating said surfaces to a temperature sufficient to form a filmcontaining a phosdescribed.

2. The process of coating metal shapes with protecting metal phosphidefilms which consists in mixing a phosphate of a metal or an alkalineearth with carbon; applying said mixture to the surface of the metal tobe coated; and heating said surface to a temperature sufficient to coatsaid surface with a film containing a phosphide of the coated metal,substantially as described.

3."The process of coating metal shapes of iron and steel with protectingmetal phos-, phide films which consists in mixing a phosphate of a metalor an alkaline earth metal with carbon; applying said mixture to thesurface of the metal to be coated; and heatingsaid' surface to atemperature of substantially 1600 F. and for a time sufiicient to coatsaid surface with a film containing a phosphide of the coated metal,substantially as described.

4. The process of coating iron and steel surfaces with a phosphide ofiron which consists in coating said surfaces with a paint like mlxturecontaining carbon and phosphorus in a phosphate combination; and

In testimony whereof Iaflix my signature.

SAMUEL PEAGOCK.

